Implantable medical devices include, among other things, cardiac rhythm management (CRM) devices such as pacers, cardioverters, defibrillators, cardiac resynchronization therapy (CRT) devices, as well as combination devices that provide more than one of these therapy modalities to a patient. Such implantable devices are typically powered by a battery. Moreover, such implantable devices are typically communicatively couplable to an external programmer or other local or distant interface device, such as an advanced patient management (APM) system that is capable of communicating with the implantable device over a computer network and/or telephonic communications network. This allows the external programmer or APM system to be used for programming operational parameters of the implantable device or for receiving from the implantable device data about the patient or about the implantable device. The effects of exercise on a cardiac patient provides useful diagnostic and prognostic information about the cardiac patient.